Fluid pump



1951 A. F. HA BENICHT 2,579,568

FLUID PUMP Filed June 25, 1948 2 -5mm 1 @Am, aw, %%%,4/

Dec. 25, 1951 A; F. HABENICHT 2,579,568

FLUID PUMP Filed June 25, 1948 2 swans-4:45:22" 2 ,hrza

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Patented Dec. 25, 1951 UNITED STATES PATENT OFFICE FLUID PUMP August F. Habenicht, Tinley Park, 111. Application June 25, 19% Serial No. 35,100

4 Claims. (01.230-184) This invention relates to pumps, and in particular to a reciprocating-piston pump for pumping gases or liquids under conditions of high ternperature and pressure.

An object of this invention is to provide a pump having positive valve action, not dependent .on the material being pumped. Another object of this invention is to provide a pump for pumping gases or liquids which is inherently free from airlocks and capable of operating at high pressures and temperatures.

.A further object of this invention is to provide an eiiectively self-priming pump in which the pumping cylinders are filled with liquid under pressure at the end of each pumping cycle, said pumping cylinders being thereby purged of all non-condensable gas. Still another object of this invention is to provide a high-pressure hydraulic actuation means having .a novel design whereby its packings are subjected only to substantially atmospheric pressure. Another object of this invention is to provide a hydraulic system in which actuation of secondary power cylinders is unaffected by the variations in load on the primary pressure source occurring during operation of the primary power cylinders. Other specific objects and advantages will appear as the specification proceeds.

r The invention is illustrated, in a preferred embodiment, by the accompanying drawings, of which-- Figure l is a view in front elevation of a pump made according to this invention; the figure is partly in section, and connecting pipes and certain other components are represented diagrammatically. Fig. 2 is a vertical sectional view taken along the line 22 in Fig. 1 and Fig. 3 is a horizontal sectional view of the pump cylinders and hydraulic power cylinders, the section being taken along the line '33 of Fig. 2.

In the illustrations, a pair of pump cylinders P' and P, containing respectively reciprocating pistons X and X, are supported in a vertical position by any suitable means (not shown). A yoke Y is aflixed near its midpoint to the upper end of piston X-and a corresponding yoke Y is affixed to the upper end of piston X. A pair of hydraulic power cylinders H, carrying pistons 19 and piston rods iii, are supported on opposite sides of cylinder P; piston rods 1 a are affixed at their upper ends to yoke Y. A similar pairot power cylinders are mounted on opposite sides of cylinder P"; power cylinders H contain respectively pistons 1 9c, carried by piston rods .118mwhich are afiixed at their upper ends toyoke Y.

Each of the hydraulic cylinders H and H is equipped at its upper end with .a stuifing box, comprising an annular internal shoulder 88 formed integrally with or welded into the cylinder, packing material 81 positioned around piston rod [8 and seated on shoulder 88, a gland 86 adapted to compress packing material 87, and a cap 25 threaded onto the top of cylinder H or H and adapted to force gland 86 downward to compress packing material 81. Annular shoulder 88, gland 86, and cap 25 all have central apertures machined to provide a snug sliding fit with piston rod 18 or IBa.

.A hollow rectangular box 22 is Welded or otherwise afiixed to the upper ends of cylinders P and P; box 22 is bored to receive pistons X and X and power cylinders H and H. Packing rings 25 seal oh the inside of box 22 from pistons P and P; rings 26 are mounted coaxially with pistons P and P respectively and are welded to the bottom plate of box 22. Packing material 24 fills the annular space between pistons X and X and packing rings 26 respectively, and within the upper end of each packing ring 26 is a bushing or gland 2|, machined to make a snug sliding fit with pistons X or X and with the inner surface of packing ring 26. Bushings 2| have annular flanges bored to receive bolts 21, which are threaded into apertures in the top of box 22 to hold bushings 2| securely in place and to cause them to press down on packing material 24.

On the top side of box 22 a pair of cylindrical sections 20 are mounted respectively coaxial with pistons X and X and are adapted to be filled with liquid, such as oil, to form a liquid seal supplementing packing 24. The inner diameter of pump cylinders P and P is substantially larger-say one-half inch-than the diameter of pistons X and X; pistons X and X are centered in cylinders P and P respectively by bushings 2 l Power cylinders H and H pass through apertures provided therefor in the top and bottom of box 22, and are securely afiixed, as by welding, to box 22. A pair of ports 28 in the sides of each of the cylinders H and H communicate with the interior of box 22. The bottom of each of the cylinders H is fitted into and welded respectively to one of apair of closed tanks 29; similarly the bottom of each of the cylinders H is fitted re spectively into one of a pair of tanks 29a. Tanks 29 are connected together by a communicating pipe 30; tanks 2911 are likewise connected together by a communicating pipe 30a.

A pair of upright supporting arms l0 and I! are afiixed. as by welding, to the upper side of box 22. Arms l3 and ii carry at their tops journal bearings l2 and I3 respectively; journalled into said bearings is an axle H5. At its opposite ends axle l6 carries a pair of sprocket wheels S. Chains C run over wheels S and connect yoke Y to yoke Y. Chains C are secured to yoke Y by bolts 3|a. Chains C are connected to yoke Y by yieldable couplings comprising bolts 3| and coil springs 32. Springs 32 operate to maintain at all times a slight tension on chains C. A pair of journal bearings l4 and i5 are welded, or otherwise affixed, to the lower side of box 22; journalled therein is an axle |1 carrying at its opposite ends a pair of sprocket wheels S. Chains C pass around wheels S and connect yoke Y to yoke Yf, chains 0' being coupled to yokes Y and Y by suitable .bolts 33 and cooperating nuts 34. Nuts 34 are adjusted to maintain chains C under slight tension. 7

, Control valveis mounted vertically in rigid relationship to cylinders H and H by any suit able means (not shown). Valve 46 includes an upper section containing a cylinder 4| and a two-section piston 48 slidable therein. A' piston rod 42 is affixed to the upper end of piston 48; it extends above'valve 4G to a level slightly higher than the highest point attained by yoke Y during the upward stroke of piston X and passes slidably through aperture 43 in the arm 35 which extends Flange members 44 and 46 are afiixed rigidly to rod 42. Member 44 is positioned near the top of piston rod 42, where it may be engaged by arm 35 during the topmost portion of the stroke of piston X, such engagement causing piston 48 to rise to its upper position as shown in the drawing. Flange member 46 is positioned on red 42 at a point near the level reached by yoke Y when piston X is at the bottom of its stroke, such that member 46 is engaged by arm 35 and piston 48 is moved to its lowered position at the time piston X reaches the lowest part of its cycle. Coil spring is affixed to flange member '44 and extends downward therebelow around rod 42; coil spring 4'! is affixed to member 46 and surrounds rod 42 thereabove.

The lower part of valve 43 comprises a cylinder 49 and a four-section piston 5c reciprocable therein. The 'upper and lower parts of valve 43 are separated by a bulkhead 5| containing a passage 52 which connects the. up

per end of cylinder 43 with a port on the side of cylinder 4! near the lower end thereof.

A check valve 53 is supported by any suitable means near thelower end of cylinder P. This valve has a cylinder 54-, a valve seat 55 in the bottom of the cylinder, a valve member 56 cooperating with the valve seat and movable in a vertical plane by rod 51. Cylinder 54 is connected to the lower end of pump cylinder P by a communicating pipe 58. 53a is connected to the lower end of pump cylinder P by a pipe 58a. Valves 53 and 53a are actuated respectively by power cylinders 59 and 59a, each of which carries within it a piston, 59 and Ella, respectively, reciprocable in the cylinder and affixed to the upper ends of rods 51 and 57a respectively.

Fluid pump 6| and its power cylinder 52 are mounted near cylinder P by any suitable means;- a similar pump fila and power cylinder 62a are mounted near pump cylinder P. Pump 6| contains a piston 53 reciprocable in cylinder 6| and fitted with a shaft 65 the upper end of which laterally from yoke Y.

A similar valve.

' pump cylinder P.

is affixed to the piston 64 of power cylinder 62. Pump fila is equipped with a similar piston 63a which is coupled by shaft 650. to piston 64a. in power cylinder 52a.

A check valve 66, having a cylinder 61, a valve seat 68, valve member 63, and shaft '10, is mounted near the upper end of cylinder P. Shaft ll! is affixed to piston 12 in power cylinder II, which is mounted above valve 66. Valve seat 68 communicates through pipe i3 with the upper end of pump cylin'de'r'P. A similar check valve 66a is mounted near the upper end of Valve 63a has a cylinder 610., a valve seat 68a, a valve member 39a, and a shaft 10a. Shaft m is afiixed at its upper end to piston 12a which is reciprocable in power cylinder Ila, mounted above valve 33a. Valve seatiifia communicates with the upper end of pump cylinder P via pipe 73a. The port in cylinder 61 is connected by pipe 74 to an out let filter '15, indicated diagrammatically onthe drawing. A branch pipe 74a connects the port in the side of cylinder 610. with pipe 54. Filter '85 has a gas outlet port 16 and a liquid outlet port i1. Port 11 is connected by pipe 18 to tank 79.

Valve I00, mounted on the pump structure by any suitable means, comprises cylinder |ll| and a four-section piston Hi2 reciprocable.

therein.

Hydraulic pressure for the operation of the various power cylinders is supplied by pumps and BI, which are indicated diagrammatically on the drawing. These may be conventional rotary hydraulic fluid pumps, driven by an electric motor or any other suitable source of energy, capable of generating hydraulic pressures of the order of two hundred to three hundred pounds per square inch. Hydraulic fluid may be stored in tank 82, which is equipped with a conventional air vent 83. Pipe 84 and its branch 84a connect tank 82 to pumps 80 and 8| respectively. The direction of flow of fluid through pumps 80 and BI is as indicated by arrows on the drawing. a a

From pump 80 pipe 85 carries fluid to a port located about midway up the wall of cylinder 4|, and through branch pipe 85a to a port about midway up the wall of cylinder 49. Pipe connects a port near the upper end of cylinder 4| to a port at the bottom of cylinder 49. Pipe 9| connects a port located on the wall of cylinder 49, about one-third of the distance up from the bottom thereof, to one of the tanks 29. Pipe 92 connects a port on the wall of cylinder 49, about two-thirds of the distance up from the bottom thereof, to one of the tanks 29a. Pipe 93 runs from a port at the top of cylinder 4| to tank 82; branch pipe 93a connects pipe 93 to a port in the wall of cylinder 49 about one-fourth the distance up from the bottom thereof; branch pipe 931) connects pipe 93 to a port in the wall of cylinder 49 about three-fourths of the distance up from the bottom; and pipe 930 connects pipe 93 to a port at the bottom of cylinder 4|.

Pipe connects a port near the top of cylinder 4| to a port at the bottom of cylinder |0|'. Pipe 95 connects a port near the bottom of cylinder 4| with a port at the top of cylinder llll. Pipe 96 serves as a communicating channel'to connect the interior chamber of box 22 with tank 82. Pipe 91 runs from the output side of pump 8| to a port midway up the wall of cylinder llll; Pipe 98 runs from a port near the top of cylinder |0| to tank 82, while branch pipe 98a connects 5 pipev 98 to a port near the bottom of cylinder II.

Pipe 99 runs from a, port in the wall of cylinder I0 I, located about three-fifths of the distance from the bottom thereof, to a port at the top of power cylinder .IIa. Branch pipe 99a connects pipe99 to a port near the bottom of power cylinder 59a. Branch pipe 9% connects pipe 99 to a port at the bottom of power cylinder 62a. Branch pipe99c connects pipe 99 to a port at the bottom of power cylinder II. Branch pipe 99d connects pipe 990 to a port at the top of power cylinder 59. Branch pipe 99c connects pipe 99d to a port at thetopof power cylinder 62. I

Pipe I03 runs from a port on the wall or cylinder IOI, about one-third of the distance up from the bottom thereof, to a port at the bottom of power cylinder lIa. Branch pipe 103a connects pipe I03 to a port at the top of power cylinder 59a. Branch pipe I'03b connects pipe I03 to a port at the top of power cylinder 62a. Branch pipe I 93c connects pipe I93 to a port at the top of .power cylinder II. Branch pipe I03d connects pipe I030 to a port near the bottom of power cylinder 59. Branch pipe I032 connects pipe mm to a port at the bottom of power cylinder 62. 1

A safety valve I05 is connected between pipes 91 and 98; this valve will normally be set to pass liquid at apredetermined pressure which may be about-150 pounds per square inch.

An inlet pipe I06 runs from the still or other object to be evacuated (not shown) to a port in check valve 53 which communicates with valve seat 55, while branch pipe I'tta connects pipe I06 to a similar portin check valve 53a, communicating with valve seat 55a. Pipe I El runs from tank I9 through check valve I08 to a port at the bottom of fluid pump 6I. Branch pipe I01a runs from pipe I01 through check valve I08a to a port J;

at the bottom of fluid pump BIa. Check valves I08 and 39a are of conventional character which will-permit the flow of liquids in one direction, regardless of pressure, but which block the flow of liquids in the opposite direction. Both valves are designed to pass liquid freely from tank 19 to the fluid pump and to prevent the flow of liquid in the opposite direction.

Pipe I09 runs from the port at the bottom of fluid pump 6I' through a spring-biased check valve IIO to a port on the side of cylinder 54. Similarly, pipe I09a connects the port at the bottom of fluid pump 6| 0; through a spring-biased check valve I We to a port on the side of cylinder 54a. Spring-biased valves H0 and II 0a are of conventional structure, preventing passage of fluid in one direction and permitting passage of fluid in the opposite direction only when it is subjected to a predetermined pressure. Both valves III] and 0:1 are connected so as to prevent flow of liquid from the valve cylinder 54 or 54a to the fluid pump 6! or BIa, as the case may be.

The invention has been described in the form adapted to the pumping of non-condensable gases, such as air or other gaseous substances which might be removed from a still or other treating chamber. .Tank I9 and the pipes and hydraulic devices associated therewith for such an application, be filled with any suitable liquid which is non-reactive with the gas to be pumped. Hereinafter, in this specification, the fluid in tank I9 and its associated elements will becalled purging fluid. If air is to be removed from. a chamber and recovery of other gases Ill mixed therewith is not desired, the purging fluid may be almost any form of oil having a boiling point substantially higher than the operating temperature to be encountered. If the substanceto be pumped is an unstable gas or mixture of unstable gases, or is a mixture of gas and liquid, or non-condensable gases mixed 'with gases which readily condense to liquid form, the purging fluid must in each case be chosen so as to be compatible with the material being pumped. in one application, wherein this invention was employed to pump semi-boiling edible juices for use in a canning operation, the purging fluid employedwas a stock of edible juices identical to those being pumped.

Filter l5 likewise may take different forms according to the particular application to which the invention may be put. If it is being used merely to pump air or some other stable gas, filter maybe simply a gravity filter designed to cause the gases to pass oii at vent It while the purging fluid flows through port 11 back to tank it. In other applicationsfilter '55 may be a much more complicated device. If the gas being pumped is to he recovered, rather than being merely vented to the atmosphere, a suitable storage tank may be provided for connection to vent 79. Similarly, if the gases being pumped comprise a mixture of several components, all of which are to be recovered, filter l5 may be a still or other fractionating device.

Operation The drawing shows the pump in the portion of its cycle wherein hydraulic cylinders H have just lifted the pump piston X to the top of its stroke. Arm 35 has just engaged piston rod 92 and caused it to move piston 48 to its upper position. As piston 48 rises, hydraulic fluid is forced by pump 89 through pipe 05 into cylinder 9i it then flows out through pipe 90 and causes piston 99 to rise to its upper position, as shown. Fluid also flows from pipe 85 through cylinder 49 and through pipe 94 to the lower end of cylinder iili, causing piston I02 to rise to its upper position, as shown. The resetting of the valves and M89 result in the following operations:

Hydraulic fluid urged by pump 80 flows through pipe a and pipe 92 into tanks 29a where it forces pistons I9a upward in hydraulic power cylinders B. As pistons I9a rise, yoke Y and pump cylinder X are raised accordingly, and chains C" and C force yoke Y downward, causing piston X and hydraulic pistons E9 to start downward. The fluid in hydraulic cylinders H can readily flow through tanks 29, pipe 95, pipe 93a, and pipe 93 back to storage tank 82, so that the hydraulic fluid on the low-pressure side the circuit does not oppose the lowering oi pistons I9.

Hydraulic fluid urged by pump iii through pipe 9'5, and pipe 99 and its ous branches, resulting in the raising of piston in power cylinder 99a, the raising of piston G la in power cylinder 02a, the lowering of piston Na in power cylinder Ha, the raising of piston i2 in power cylinder II, the lowering of piston 9 in power cylinder 62, and the lowering of piston in power cylinder 59. All these operations are accomplished without substantial resistance from the hydraulic fluid, since pipe I03 and its various branches communicate through cylinder ltl with pipe 98, which carries the fluid on the low-pressure side of the circuit back to storage tank 82.

, Since pump 8| maintains a high and constant hydraulic pressure in the part of the circuit controlled by it, the various power cylinder operations just mentioned are rapid and positive. The raising of piston 69a and the lowering of piston 69 cause inlet check valve 53a to open and inlet check valve 53 to close. As a result, the fluid being pumped flows through pipe llllia and 58a into pump cylinder P. Meanwhile, as piston X rises in pump cylinder P, purging fluid is being forced at high pressure out of fluid pump 6! as piston 53 is driven downward therein. The purging fluid passes through valve H and pipe 58 and forces its way upward in cylinder P as piston X comes down. The cubic capacity of fluid pump 6| is somewhat greater than the cubic capacity of cylinder P when piston X is fully lowered therein; consequently, by the time piston X has reached the bottom of its stroke, cylinder P is completely filled with'purging fluid and all of the gas in the cylinder, including all the material being pumped, has been forced out of cylinder P and into pipe 14, which carries it to filter i5. Filter i separates the purging fluid from the gas; the purging fluid returns to tank 19 through pipe 18, and the gas is passed through vent 18 to atmosphere or to a storage tank as may be desired.

While the foregoing events are taking place, outlet check valve 66a has been closed by the lowering of piston 12a, and the material to be pumped has been flowing into cylinder P. Piston 64a in power cylinder 62a has been rising and carrying with it piston 69a in fluid pump 6 la, drawing purging fluid from tank 19 into the cylinder of fluid pump Sla Spring-biased valve iita prevents purging fluid from passing into pump cylinder P during the up-stroke of piston X, it being adjusted so that it will yield to the pressure exerted upon it by the down-stroke of piston 93a but not to the much lower pressure resulting from the up stroke of piston X. Spring-biased valve H0 is similarly adjusted so as to permit passage of purging fluid into pump cylinder P during the down-stroke of piston 63 but to prevent purging fluid from entering cylinder P during the up-stroke of piston X.

When the pump piston X reaches the bottom of its stroke, arm 35 engages spring 41 and flange and piston 48 is caused to assume its lower 7 position. Thereupon hydraulic fluid urged by pump 89 flows through pipe 85 and passage 52 into the top of cylinder 49, causing piston 50 to move to its lower position. Fluid also flows through pipe 85a and pipe 9| into tanks 29, causing hydraulic pistons Hi to start upward in power cylinders H. Fluid likewise flows from pipe 85 through pipe 95 into the top of cylinder HH,

causing piston Hi2 to'assume its lower position. Gn the low-pressure side of the pump 99 circuit, fluid forced out of hydraulic cylinders H by the dropping pistons l9a flows through pipe 92, pipe 99b, and pipe 93 back to storage tank 82. The shift in position of piston I02 in valve H19 causes fluid urged by pump 8| to flow through pipe I93 and its various branches to reverse the positions of the pistons in power cylinders 62a, Ha, 59a, 52, 71, and 59. The low-pressure side of the pump 8! circuit is now completed back to storage tank 82 through pipe 99 and its various branches, in conjunction with cylinder I0! and pipe 98.

Thus, in this part of the cycle, the fluid being pumped passes from pipe I06 through the nowopen inlet valve 53 into pump cylinder P. Inlet valve 53a is closed during this part of the cycle. Purging fluid is forced into pump cylinder P" as" piston X drops therein, resulting'inthe complete purging of all gases from cylinder P and the exhaust thereof through the now-open outlet valve 66a to fllter I5. i

The cycle of operation described in the foregoing paragraphs may take place, in a practical embodiment of the invention, at a rate of from 20 to 40 times per minute. It has been found that this invention, operating as a vacuum pump, can maintain a pressure of less than 3 mm. of mercury in a treating chamber continuously for days. No airlocks can occur to interfere with the operation of the pump, and the valve action is positive, so that it is equally efiective whether the vapor pressure of the material being pumped is great or small.

One novel feature of the invention deserves particular mention, since it contributes largely to the successful operation of the pump in long periods of continuous service. This is the novel arrangement by which the packing atthe upper ends of hydraulic cylinders H and H are not subjected to high pressures. Ports .28 provide communication between the interior of box 22 and cylinders H and H. Hydraulic fluid may, under the very high pressures here involved, leak in small quantities past pistons i9 and Na. In this invention, any such leakage flows from the interior of box 22 through pipe 96 back to hydraulic fluid storage tank 82. Thus no such leakage is lost from the hydraulic system, and the packings provided at the upper ends ofthe hydraulic power cylinders H and H are not sub-v jected to high pressure, since the interior of box 22 is at atmospheric pressure.

Another special advantage which this invention possesses over. other pumps adapted to pump gases and liquids is the very wide range of temperatures and pressures at which it will operate smoothly and efflciently. It has been'found that the pump will operate with complete satisfaction at temperatures within three or four degrees of the boiling point of the purging fluid, and at pressures ranging up to several hundred pounds per square inch. While a particular embodiment of the invention has been shown and described in this specification in considerable detail for purposes of illustration, it will be understood that the structural details may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In apparatus for pumping gases, a cylinder, a piston reci-procable therein having smaller cross-sectional area than the cylinder, an inlet conduit near the bottom of the cylinder, an outlet conduit near the top of the cylinder, means for reciprocating the piston, an outlet valve in the outlet conduit, a gas line communicating with the inlet conduit including an inlet valve, means operative to close the outlet valve and open the inlet valve during the up-stroke of the piston and to open the outlet valve and close the inlet valve during the down-stroke of the piston, and liquidpressure means communicating withthe inlet conduit for admitting liquid under pressure into the inlet conduit during the down-stroke of the piston to force the gas out of the outlet conduit.

2. In apparatus for pumping. gases, a cylinder, a piston reciprocable therein having smaller cross-sectional area than the cylinder, an inlet port near one end of the cylinder, an outlet port near the other end of the cylinder, an outlet valve on the outlet port, a gas line communicating with the inlet port including an inlet valve, 9. liquid source, means including a liquid pump connecting the liquid source and the inlet port, and hydraulic motor means operative to reciprocate the piston, to close the outlet valve and open the inlet valve while the piston is moving away from the inlet port, to open the outlet valve and close the inlet valve while the piston is moving toward the inlet port, and to actuate the pump while the inlet valve is closed to force liquid under pressure into the cylinder and thereby to force the gas out of the outlet port.

3. In apparatus for pumping gases, a first cylinder and a second cylinder, a piston in each cylinder reciprocable therein having smaller crosssectional area than the cylinder, an inlet port in each cylinder near the bottom thereof, an outlet port in each cylinder near the top thereof, means for reciprocating the pistons in opposite phase, an outlet valve on each of said outlet ports, a gas line, means including a first inlet valve coupling the gas line to the inlet port of the first cylinder, means including a second inlet valve coupling the gas line to the inlet port of the second cylinder, means operative to close the outlet valve of the first cylinder, to open the inlet valve thereof, to open the outlet valve of the second cylinder and to close the inlet valve thereof during the up-stroke of the piston in the first cylinder and to reverse the position of all said valves during the down-stroke of said piston, and means for admitting liquid under pressure into the inlet port of each cylinder during the down-stroke of the piston in such cylinder.

4. In apparatus for pumping gases, a first cylinder and a second cylinder, a piston in each cylinder reciprocable therein having smaller crosssectional area than the cylinder, an inlet port in each cylinder near one end thereof, an outlet port in each cylinder near the other end thereof, an outlet valve on each of said outlet ports, a gas line, means including a first inlet valve coupling the gas line to the inlet port of the first cylinder, means including a second inlet valve coupling the gas line to the inlet port of the second cylinder, a liquid source, means including a first liquid pump connecting the liquid source to the first inlet port, means including a second liquid pump connecting the liquid source to the second inlet port, and hydraulic means operative to reciprocate the pistons in opposite phase, to close the outlet valve and open the inlet valve of each cylinder while the piston therein is moving away from the inlet port, to open the outlet valve and close the inlet valve of each cylinder while the piston therein is moving toward the inlet port thereof, to actuate the first liquid pump while the piston in the first cylinder is moving toward the inlet port thereof to force the gas in said first cylinder out or the first outlet port, and to actuate the second liquid pump while the piston in the second cylinder is moving toward the inlet port thereof to force the gas in said second cylinder out of the second outlet port.

AUGUST F. HABENICH'I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 421,346 Berrenberg Feb. 11, 1890 1,415,852 Van Horn May 9, 1922 2,292,543 Patterson Aug. 11, 1942 2,462,246 Worthington et a1. Feb. 22, 1949 2,465,485 Robinson Mar. 29, 1949 

